Successive antenna selector



H. O. PETERSON SUCCESSIVE ANTENNA SELECTOR IJun@ 11, 1935.

Original Filed Nov. 16, 1928 2 Sheets-Sheet 1 figg, i

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#WEA/MQ III wf/wv@ INVENTOR HA D o. riT'ERsoN oRNEY June 11, 1935. H. o. PETERSON 2,004,128 l SUCCESSIVE ANTENNA SELECTOR Original Filed Nov. 16, 1928 `2 Sheets-Shet 2 INVENTOR Rom o. PETERSON BY@ TTORNEY Patented June 11, 1935 i i Y y 2,004,128

NUNITED STAT-ESPATENT OFFICE Harold 0. Peterson, Riverhead, N. Y., assignorto iRadio Corporation of America, a corporation of Delaware Y Application November 16, 1928, Serial No.' 319,939 i Renewed April 12, `1933 so claims. (012509-211) This invention relates to the reception of radio least partially overcoming two difficulties which signals, and more particularly to antenna s'elec- 1 `will next be described. In order to control the tion for diversity receivers for the reductiono volumeof the combined output from thediversity fading of high frequency signals. f antennas it has been proposed to equip each `of Communication on very high frequency carthe ampliers for each ofthe antennas with a 5 riers is economioalof power, but is handicapped volume control, but ihe, inv additien G0` requiring by the prevalence of fading. Inasmuch as fad a considerable number of volume controls, suffers ing may differ very widely at geographically from a much greater disadvantage in that the spaced points, or in different planes-of polarizaamplifiers rOf these antennas at Which fading iS l0 tion, it has been` proposed to `reduce its effect by prevalent are given increased gain, in Consequence 10 diversity systems of Vreception characterized by of which the noise level of the amplifier output, the use of a number of antennas having different and'consequently of the combined signal, is great' fading characteristics. Because the phase of the i lyiinereased, and, in the CaSe 0f fading 0f the lradio' frequency energy at the different points of l carrier when receiving speech modulated signals, collection may fluctuate considerably it is`not the distortion caused by the beat between side `15 feasible to combine the received energies dibandsis unduli7 magnified. i rectly together. One suggestion to overcome this The seoonddifficulty, like the latter of the two diinculty is to switch rapidly from one antenna disadvantages already mentioned,` arises onlyin to another in the series, but this scheme suffers the case of the reception of speech or speechv from the disadvantage that the antenna at which Simulating Signals, Where the JlaIlSIliSSiOll energy 20 fading is not prevalent is coupled to the receiver 'is radiated in the form of a carrier and sideV only intermittently. Another and valuable meth- 1 bands, for relative phase fluctuations in closely od is to combine `the received energies after recadjacent frequencies, such'as side band and cartiiication but this is not perfect because thevolf rier frequencies; sometimes occur even at `one urne of the received energy is apt to vary between i antenna. This causes similar phase fluctuations 25 the extremes of almost complete fading on all of i in the'beat of Ythe carrier and side bands, for if the antennas, to a total absence of fading on `of two beating WaVeS One iSV kept COnStant inl any of the antennas. phase, While the` other is shifted in phase, theirv To overcome this `disadvantage is one object beat is equally shifted in phase. It therefore a0 of my invention, which I accomplish bya method i follows that although the carrier and side band 30 which includes collecting signal energy on apluenergies 'eXperienCe Only radio frequency dif,- rality of antennas, and feeding the collected-enyfeieneeS in phase, these differences `are transergy to a receiver from only so many-of the'anferred to the detected or` audio` frequency enertennas as may be necessary to keep the energy i gies, so that`it is as impossible to combine the 8B supplied to the receiver at a predetermined dedetected energies aS it iS t0`diIee'G1y Cembine the 35 sirable value. From one aspect theinvention `originally'collected radio frequency energies. may be considered to be a volumeY control in Theforegoing difficulties may be overcome by which the adjustment of the volume is attained automatically switching the receiver to only a. by connecting a variable number of antennasof i single antenna at which fading is not prevalent,

40 any type or spacing to a receiven From another and such la system has been disclosed in a co- 40 aspect the invention may be considered as a dipendingV application 0f Jehu, Blf MOOIe, Serial versity factor'receiving arrangement in which Number 319,768, filed November-idf 1928. The antennas having relatively different fading char- `present systeml is smooth in operation and simacteristics are successively coupled to a receiver ple in' apparatus, and to a very considerabledevuntil an antenna at which fading isfnot preva- -gree possessesthe advantages of the system re- 45 lent is reached. result is accomplished by ferred to, for during a great deal of the time all A employing separate amplifiers with the antennas, of the antennas except the iirst'are not coupled combining the outputs from the ampliiiers, and to the receiver, and except at veryV rare intervals controlling the gain in the ampliers at graduat least some of the antennas are not coupled ated amounts from a common volume control to the receiver. f l i responsive to the volume ofthe combined energy, The invention is describedr more in detail in so that more ofthe amplifiers are made conducthe following specification, which is accompanied ltive as the volume of the combined energy is by drawings in which decreased. Figure 1 is a wiring diagram of one form of This system has two further advantages in at my invention; V5.5 i

j shown in Figure 2.

' Y transformer I 4, the secondary of 4`which is Vcou-` Figure 2 is an arrangement in which the signal energies are combined after rectification; and

Figure 3 is a modification of the arrangement Referring to Figure l it will be seen that there are a plurality of antennas 2, and 6,

which, for diversity Work, may be -given rela-V tively diierent fading characteristics in any suitable manner, such as by xbeing geographically spaced, orby being positioned in different planes of polarization. The antennas are respectively coupled to an aniplier 3, Ill, :and l2, the foutputs from which are combined at a `common pled to a common receiver t6, and a common volume control I8. This has been indicated in simple form as comprising ,a detector 22B, the anode circuit of which thereis a battery .-22 and a resistance 24 which is grounded at .26 to complete the anode circuit. A condenser 28 is connected in parallel with'resistance 24, .and the magnitude :of this condenser is properly `chosen Ato give'tlle volume control the desired time vconstant, which, of course, should be made appre- :ciably lower Ethan the vrate of signal modulation, `-Whether it be code or speech, in order that the 4volume control may not attempt to destroy lthe incoming signals. Y Y,

4The amplier i8 is lsuitably `biased so that it is .always eiective to amplify and 4transmit .signel energyrco'llected on the antenna :2. The arn- -plirler H3 is biased with a more negativejbias, .either entirelyor partially by reason of the bias poten-tial lobtained across the portion of the Vresistance 2a lying between ground and the point Y Sii. When the signal volume decreases the cur- :ren-trw :through the resistance 24 decreases, :ainrconseonence of which the negative bias produced at `the :point 3i) decreases, that is, the bias 'tis made more positiye, so `that `the amplier le isfniade eiective to ,amplify and transmit energy collected at'the antenna 14 tothe receiver i6 and the volume control zl- Y .In ,a similar amanner the amplier -I2 is biased 'still Vincre negative lbythe bias lead 3e, which 'is connected `to the resistance '24 at the point e6. 'this :manner the amplifier 12 rwill be parade effective to supply energy to the receiver, 'should `.that prove necessary .to keep the volume zat the desired amount, but only after an attempt has `:been :made to satisfy this requirement, first by antenna 2, ,and then by .antenna 2 suppleroented rby antenna-4. f Y Further antennas may be provided, as is indicated by the additional `coupling coil 33 of the transformiert-, .and the additional bias lead liti. The arrangement shown directly lcombines the received radio ,frequency energies,but in these energies relative4 fluctuations in phase areV apt to cur. This is not so serious a disadvantage Vfin Vthis-ssystern as with otberabecause for the most p artV antenna 4y will' be .connected onlywhen -fading isp'revalent at `antenna 2,and so on, in

'.arid 14d at a low potential.

tennas Ell, 52, and 54, from which transmission lines 5t, 58, and 60 run to radio frequency ampliiiers 62, 64, and 63. For the sake of simplicity only one vacuum tube stage has been indicated in these amplifiers, but in practice several stages may be arranged in cascade. The amplified energies are fed to detector tubes 63, iii, and l2, `across the output circuits of Whichltersections lil are connected, to bypass the radio frequency components of the detected energies. The anodes of the detector tubes are connected together and to anonimo); source of anode potential 15, in series with which thereV is a coupling impedance I-B, and lavolurne control impedance Sil. In parallel with the volume control impedance a condenser 82 is connected for determining tlie time constant .of the 4volume control operation. To one terminal of the impedance Bil a plurality of sources ci different uned potentials are connected, which may take Vthe form of a single bias battery L84 provided -withidiirerent potential taps,

and to the various taps Aon this battery there connected .the leads 86, '238, ane-l ce, which AAreir-i to the control electrodes .ofY the Yamplifier tubes.

-ua-ted values,:and these values are socliosen that only the first :amplier :is 'normally conductive, but upon decreased .output because =of fading .at .the :first Vvantenna the lpotential drop across the .impedance 8u `is reduced, which raises Y:the Vpctential at lthe vupper yendoi the impedance, Aand thereby raises all of ythe bias potentials suiiicicntly to :maire the amplier VKill conductive, but not to make the ainplier .Eli conductive, except upon st-ill further ,reduction .in the value of the com# bined .energy output. LOn lthe other hand xtlie gain in amplifier '.62 fis automatically decreased vshould the signal l:from antenna '255i .alone prove too strong, for in .this modiflcationau of the ainpliiiers are volume controlled.

One or mo-resuitable amplifier Vstages B2 may VAoptionally be coupled to the coupling impedance 18, and anydesired form of translating device 94 is coupled to the ampli-er.

Instead of a fixed diierence in bias a variable f diierenc'e may fbe .providedVand a modi'iication `embodying this feature is indicated in Figure 3, in which there are a number of preferably gecgrapnically spaced :antennas lili?, lad, me, and

VV|538, each .coupled to :an amplifier'lll'r, llc, ile,

and Hi8, the .outputs from which are fed to de" tectors 122,122, 12B, :and t28., respectively. The rectified outputs .are vconnected 'Lto a common line |30, and fed `to a coupling resistance |32, which is coupled through an amplifier to a trans lating device |34; 'The anode potential for the detector tubes is provided from a common source preferably located at 35, as is indicated on the drawings, in order toV keep the impedances '32 The'combined energy `is also fed to a volume control resistance lll-i5, in series with the coupling resistance v.532. A condenser 142 is connected in `parallel with the volume control resistance 146 in order to establish the time constant at which the volume control functions.

As in the arrangement shown in'Figure l, the various 'ampliers are biased at different bias connected to the resistance M5 at suitably chose: different points. If necessary these leads may include sources of xed potential 55., i555, and 158, the potential values ci which are chosen to give the amplifiers the desired initial bias. v `This arrangement operates liketlie arrangement 'i' fili) Vvalues by leads IM, M6, and'lc, which are' MU to the amplifier H2, in order to provide volume control for the first antenna, |02.' But itis -similar to the arrangement shown in Fig. l in that the bias values are altered differently,fthat is, in Fig. 2 the changes'caused in the initially different biases are equal, Whereas in Fig-'Sytliev changes of bias are unequal, though the rate of change of bias may be kept equal, for it' depends on the rate of flow of current through the resistance 14D, andthe spacing of the taps on the With this arrangement all of the amplifiers may be made conductive and equally biased, for little or no signal strengthpinstead Yof the first amplifiers receivingan excessive posi- Upon increased signal strength the i tive bias. later amplifiers are rapidly cut out in succession by growingV graduated negative biases,which increase in geometric ratio.

I claim:

l. The method of controlling `the volume of radio signals which includes collecting signal energy on a plurality of antennas, and automatically feeding in response to collected signal energy the collected energy-to a receiver from only so many of the antennas as `may benecessary to keep the energy supplied to the receiver at a predetermined desirable value.

2. The method of controlling 'thevolurne of radio signals which includes collecting` signal energy on a plurality of antennas, and effectively automatically coupling in response tocollected signal energy the antennas successively to areceiver until an antenna is reached atwlich fading is not prevalent, so that the energy supplied to the receiver is kept uptoA a predetermined desirable value. 7

3. The method of controlling the volume of radio signals which includes collecting signal energy on an antenna, feeding the `collected. energy to a receiver, collecting signal energy on another antenna, and automatically feeding `in response to collected signal* energy the latter energy to the receiver only when the energy fed tothe receiver from. the rst antenna falls below a predetermined desirable value.

4. The method of controlling the volume of radio signals which includes collecting signal energy on a plurality of antennas, automatically feeding in response to collected signal energy the collected energy from one of the antennas to a 1 receiver, automatically feeding in `response to collected signal energy the collected energy from another of the antennas to the receiver when the aforesaid energy falls below a predetermined desirable value, and automatically feeding in response to collected signal energy the collected energy from another antenna to the receiver when the sum of the aforesaid energies falls below the predetermined desirable value, and so 5. The method of reducing fading when receiving high frequency signals which includes simultaneously making a plurality of energy col-` le'ctions of different fading characteristics, and automatically feeding in response to collected signal energy only as many of the collected energies to a common receiver as may be necessary to keep the energy supplied to the receiver at a predetermined desirable value.

6. The methodofreducing fading when regeographically value.` l

' 13. A radio signallvolume control 'system com# ceiving high frequencysignalswhich includes collecting signal energy on -a plurality of antennas having different fading characteristics, and effectively automatically coupling in` response to collectedsignal energy the antennas successively to t a receiver until an antenna is reached at Which fading is not prevalent, so that the energy supplied to the receiver is kept up to a predetermined desirable value.

ing characteristics, and automatically feeding in response to collected signal energy the latter energy to the receiver only When the energy fed tothe receiver from the first antenna falls below aipredetermined desirable Value. y

8. The method of reducing fading Vwhen rei,

ceiving high frequency signals which includes collecting signal energy on a plurality of antennas so relatively positioned that the fading characteristics thereat usually differ, feeding the collected energy from one of the antennas toa "receiver, automatically feeding in response to collected sig'- nal energy the collected energy fromV another antenna to the receiver only when fading is prevalent atthe aforesaid antenna so that the energy supplied thereby falls below a predetermined desirable value, `automatically feedingin response to collected signal energy from another antenna to the receiver only when fading is prevalent at the aforesaid antennas so that the sumY of the energies supplied thereby falls below'a predetermined desirable value, and so on.

9. The method of reception which includes collecting the radiated energy l on a plurality of antennas, separately amplifying the collected energies, combining theamplified energies, and controlling the gain in the amplifiers at graduated amounts in response to the combined energy so that more of the amplifiers are made conductive as the volume of the combined energy decreases.

10. Thel method of reception which includes collecting signal energy on a plurality of spaced antennas, amplifying the collected energies, separately detecting the amplified energies, combining the detected energies, controlling the gain in the aforesaid step oframpliiication at graduated'amounts separately in response to the volume of,y the combined energy, so that more of the amplifiers are made conductive as the volume of the combined energy combined rectified energy for translation; v i

decreases, and utilizing the ,11. `A radio signal volume control system comprising a plurality `of antennas for collecting signal energy, a receiver, and biasing means responsiveto collected signal energy for effectively Vcoupling only'so many ofthe antennas to the receiver as may be necessary to supply thereceiver with a predetermined4 desirable amount of energy. Y

l2. A radio signal volume control system com.-

the coupling means effective in Vsuccession until an antenna is reached at which fading is not prevalent, so that the energy supplied to the receiver is kept up to apredetermined desirable 'prising a first antenna, a receiver coupledthereto, a second antenna, and automatically biasing ymeans responsive to collected signal energy for controlling the flow of energy from the second antenna to the receiver when the energy from the rst antenna falls below a` predetermined vdesirable value.

v14. A radio signal Volume control system comprising a plurality of antennas, a receiver, means coupling a first antenna to the receiver, biasing `different fading characteristics, a receiver, and `self acting means responsive Vto collected signal energy for effectively coupling only so many of Athe antennas to the receiver as may be necessary to supply the receiver with a predetermined de- 16. A radio receiving system for reducing fadJ ing comprising a plurality of v.antennas having di-iferent fading characteristics, a receiver, means coupling the antennas to the receiver, and self 4.acting means responsivey to collectedV signal en- Y -ergy for making the coupling means effective in succession until an antenna is reached at which fading is not prevalent, so that the energy sup- A.plied tothe receiver is kept up to a predetermined desirable Value. Y

17. A radio receiving system for reducing fading comprising an antenna, a receiver coupled thereto, a second antenna having fading characteristics different from the first antenna, and

selfI actuating means responsibev to collected signal energy for feeding energy from the second antenna to the receiver only when the energy from the first antenna falls below a predetermined desirable value.

V18. A radio receiving system for reducing fad- ,ing comprising a plurality of antennas having .different-fading characteristics, a receiver, means coupling a first antenna to the receiver, self actuating means responsive to collected signal energy for feeding energy from a second antenna to the receiver only when fading is prevalent at the first antenna so that the energy supplied thereby falls below a predetermined desirable value, self actuating means responsive to collecti ed. signal energy for feeding energy from athird antenna to the receiver only when fading is prevalent at the first and second antennas so that the sum of. the energies supplied thereby `falls below the predetermined desirable value, rand so on.

19. A radio receiving system comprising a plurality of antennas, an amplier for each of said antennas, a common receiver and a common volurne control coupled to all of said ampliers, and

means responsive to said volume control for so varying the bias of the ampliers that more of the amplifiers are made operative as the volume of energy is decreased, in order to keep the total volume at a predetermined desirable value. 20. A radio receiving system comprising a plurality of geographically spaced antennas, an amplier and aldetector for eachofl said antennas,

a common receiver; and volume control responsive to the outputs ofV all of said detectors, means responsive to the VVolume control'for so varying the bias of the amplifiers that only so many. of the amplifiers are made operative as may prove necessary to keep the sum of the'rectified energies at a predetermined desirable value, and means to translate the combined rectiedenerev.

21. A fading elimination system comprising a plurality. of antennae; anamplier coupled to each antenna;V a common combining circuit for combining the outputs of. all of said amplifiers; translating means coupled to the commoncombiningcircuit; means, independent of said translating means, for rectifying energy from a plurality of said ainpliers; a resistance in series with said rectifying means whereby the rectified energy flows through said resistance; a volume control connection connected between one of said ampliers Aand a point on said resistance; and, another volume control connection connected between another one ofpsaid amplifiers and a different'point on said resistance.

22.l In combination a vplurality of antennae, an amplifier coupled to each ofV said antennae, a rectifier for rectifying the energy outputs of a plurality of said ampliers, a resistance serially connected with said rectifier whereby the rectied energies flow-serially through said resistance, and, a plurality ofv vvolume control connections connected to different points on said resistance and Yto a corresponding number of 'different ampliiiers.

23. In combination, a plurality of antennae, a radio frequency amplifier coupled to eachof said antennae, a'common combining circuit, each of. said amplifiers feeding radio frequency energy into said common combining circuit, adetector and radio receiver coupled to said common combining circuit, a rectifier having a resistance seriallyV connected in its output circuit coupled to said ,combining circuit, and, volume control connections connected from all of said amplifiers but quency circuits inresponse to the detected outv puts in said resistance. v

25. In combination, a pluralitypf antennae, an ampliiier coupled to each of said antennae, a detector coupled to each of said amplifiers for detecting the outputs of said amplifiers. a resistance, means for feeding the detected energies serially through said resistance, and, volume control connections connected to different points along said resistance to different ones of said amplifiers;

26. In combination, a plurality of antennae, an

27. In combination, a plurality of antennae, an electric discharge device coupled to each of said antennae to receive Waves therefrom, means for producing a control potential which is a function of the amplitude of the Wave output from each of said devices, and means responsive to said potential for controlling said `devices to render inoperative at least for the transmission of Waves of small amplitude those in Which the amplitude of the received Wave is small compared to that of the received wave in another;

28. In combination, a plurality of antennae so related to each other that the received Waves vary diiierently at the several receivers with Variations in transmission conditions that reception conditions vary differently at each, a plurality of electric discharge devices each having an anode, a cathode and a control element, means for supplying the Waves received in each of said antennae to a corresponding one of said devices, means for producing a unidirectional t electromotive force having at any instant an amplitude which is a function of the amplitude of the received Waves, means for impressing said electromotive force upon the control electrodes of said tive for the transmission of waves of said lower amplitudes, and a signal receiving circuit connected to receive Waves transmitted by any of said devices. Y

29. In a signaling system subject to variable transmission conditions, a plurality of receivers each receivingthe same signal and so related to each other that the received signals vary diierently at the several receivers With variations in transmission conditions, each receiver comprising an electric discharge device, a signal circuit common to said receivers, means for producing a unidirectional potential Which is a function of the amplitude of the input to said signal circuit, and means for impressing said unidirectional potential between the electrodes of said electric discharge devices to render inoperative those of said devices in which the amplitude of the received wave is small compared with that of the received Wave in another of said devices.

30. In combination, a plurality of radio signal receivers, means for combining the signal output of said receivers, and means for automatically controlling over a continuous range the gain of one of said receivers in response to the amplitude of the signal from said means for combining the signal output of said receivers to render substantially inoperative said one of said receivers when the amplitude of the signal Wave received thereby is materially lower than the amplitude of the signal Wave receivedby another of said signal receivers.

HAROLD O. PETERSON. 

